This application claims the benefit of Korean Application No. 2002-27271, filed May 17, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to air conditioners, and more particularly to a system air conditioner having a plurality of indoor units and method of controlling the air conditioner.
2. Description of the Related Art
In general, air conditioners are machines that automatically and appropriately condition indoor air in residential or office buildings by controlling properties of the indoor air, such as temperature and humidity. Since residents of such residential or office buildings typically desire to accomplish different target conditions of indoor air, and atmospheric environments of the buildings frequently vary, required air conditioning capacities of the air conditioners are frequently changed.
A system air conditioner, in which a plurality of indoor units are connected to a single outdoor unit, is a built-in air conditioner which is planned and designed in accordance with factors such as the air conditioning capacities and locations of the indoor units during a planning or designing stage of a building. In the system air conditioner, refrigerant pipes connected to a single outdoor unit are connected in series to one another to form a single pipeline with a variety of types of indoor units having various capacities and structures, such as, for example, duct type, cassette type and/or wall mounted type indoor units. Therefore, the required air conditioning capacities of the indoor units in the system air conditioner may be different from one another. Furthermore, the indoor units of the system air conditioner are mostly operated independently such that a total required air conditioning capacity of the air conditioner calculated by summing up the individually required air conditioning capacities of the indoor units is variable.
As an example of variable-capacity compressors used in a variable-capacity system air conditioner, a variable-rotation number compressor has been proposed and used. The variable-rotation number compressor is designed such that its compressing capacity is controlled in accordance with a required air conditioning capacity. Thus, the variable-rotation number compressor is controlled by controlling a rotation number of a motor thereof by changing a frequency of a current applied to the motor through inverter control.
Accordingly, it is an aspect of the present invention to provide an air conditioner and control method thereof, which is capable of rapidly shutting off refrigerant supply when refrigerant is leaked out of a refrigerant pipe connected to indoor units, and restoring leaked refrigerant into an outdoor unit.
The foregoing and other aspects of the present invention are achieved by providing an air conditioner having an outdoor unit, at least one indoor unit and a compressor. The outdoor unit is connected to the indoor unit by a refrigerant pipe to form a closed circuit. The refrigerant pipe is divided into high and low pressure pipes. The air conditioner includes a refrigerant leakage detecting unit provided on the indoor unit to detect refrigerant leakage, a high pressure pipe shutoff valve provided on a high pressure pipe of the refrigerant pipe to shut off a flow of refrigerant between the outdoor unit and the indoor unit when the refrigerant leakage is detected, and a low pressure pipe shutoff valve provided on a low pressure pipe of the refrigerant pipe to shut off a flow of refrigerant between the outdoor unit and the indoor unit when the refrigerant leakage is detected. Refrigerant within the indoor unit is restored into the outdoor unit by dosing the high pressure pipe shutoff valve and opening the low pressure pipe shutoff valve when the refrigerant leakage is detected.
The foregoing and other aspects of the present invention are achieved by providing a method of controlling an air conditioner having an outdoor unit, at least one indoor unit, a compressor, an electric expansion valve, a high pressure pipe shutoff valve and a low pressure cutoff valve. The outdoor unit is connected to the indoor unit by a refrigerant pipe to form a dosed circuit. The refrigerant pipe is divided into high and low pressure pipes. The electric expansion valve is provided on the refrigerant pipe to vary pressure of refrigerant flowing into the indoor unit. The high pressure pipe shutoff valve is provided on a high pressure pipe of the refrigerant pipe, and the low pressure pipe shutoff valve is provided on a low pressure pipe of the refrigerant pipe. The method includes restoring leaked refrigerant by keeping the high pressure pipe shutoff valve dosed and the low pressure pipe shutoff valve opened for a preset period of time when refrigerant leakage is detected, and closing the low pressure pipe shutoff valve and stopping the compressor when the preset period of time elapses.